|Short description=a shell tool for executing jobs in parallel using one or more computers

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|Full description=For each line of input parallel will execute command with the line as arguments. If no command is given the line of input is executed. parallel can often be used as a substitute for xargs or cat {{!}} sh.

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|Full description=GNU Parallel is a shell tool for executing jobs in parallel using one or more computers. A job is can be a single command or a small script that has to be run for each of the lines in the input. The typical input is a list of files, a list of hosts, a list of users, a list of URLs, or a list of tables. A job can also be a command that reads from a pipe. GNU Parallel can then split the input and pipe it into commands in parallel. If you use xargs and tee today you will find GNU Parallel very easy to use as GNU Parallel is written to have the same options as xargs. If you write loops in shell, you will find GNU Parallel may be able to replace most of the loops and make them run faster by running several jobs in parallel. GNU Parallel can even replace nested loops.

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GNU Parallel makes sure output from the commands is the same output as you would get had you run the commands sequentially. This makes it possible to use output from GNU Parallel as input for other programs.

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For each line of input, GNU Parallel will execute command with the line as arguments. If no command is given, the line of input is executed. Several lines will be run in parallel. GNU Parallel can often be used as a substitute for xargs or cat{{Pipe}}bash.

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The GNU Parallel distribution also includes an 'sql' script which aims to give a simple, unified interface for accessing databases through all the different databases' command line clients, and a 'niceload' script to slow down or suspend a program if system activity is above a given threshold.

|Documentation note=Documentation for GNU Parallel is available online at [http://www.gnu.org/software/parallel/man.html gnu.org/s/parallel/man] . Screencasts videos can be found at [http://commons.wikimedia.org/wiki/GNU_parallel http://commons.wikimedia.org/wiki/GNU_parallel].

Revision as of 18:12, 5 January 2014

GNU Parallel

https://www.gnu.org/s/parallel/Parallel is a shell tool for executing jobs in parallel using one or more computers. A job is can be a single command or a small script that has to be run for each of the lines in the input. The typical input is a list of files, a list of hosts, a list of users, a list of URLs, or a list of tables. A job can also be a command that reads from a pipe. GNU Parallel can then split the input and pipe it into commands in parallel. If you use xargs and tee today you will find GNU Parallel very easy to use as GNU Parallel is written to have the same options as xargs. If you write loops in shell, you will find GNU Parallel may be able to replace most of the loops and make them run faster by running several jobs in parallel. GNU Parallel can even replace nested loops.

GNU Parallel makes sure output from the commands is the same output as you would get had you run the commands sequentially. This makes it possible to use output from GNU Parallel as input for other programs.

For each line of input, GNU Parallel will execute command with the line as arguments. If no command is given, the line of input is executed. Several lines will be run in parallel. GNU Parallel can often be used as a substitute for xargs or cat
bash.

The GNU Parallel distribution also includes an 'sql' script which aims to give a simple, unified interface for accessing databases through all the different databases' command line clients, and a 'niceload' script to slow down or suspend a program if system activity is above a given threshold.

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